Alkyl-n-alkyl-chlorophenoxythioacetimidates

ABSTRACT

Alkyl-N-alkyl-chlorophenoxythioacetimidates are prepared by reacting N-alkyl-di- or trichlorophenoxythioacetamide with alkyl iodide in the presence of sodium alcoholate. The compounds are useful as herbicides.

United States Patent [1 1 Rumanowski [54] ALKYL-N-ALKYL-CHLOROPHENOX-[21] Appl. No.: 183,247

Related U.S. Application Data [62] Division of Ser. No. 839,078, July 3,1969, Pat. No.

[52] U.S. Cl. ..260/453 R, 260/551 R [5 I] Int. Cl ..C07c 119/20 [58]Field of Search ..260/453 R; 71/98 1 51 Feb. 6, 1973 [56] ReferencesCited UNITED STATES PATENTS 3,268,539 8/1966 Levy ..260/453 R 2,412,51012/1946 Jones ..71/98 2,811,526 10/1957 Burtner ..260/453 R FOREIGNPATENTS OR APPLICATIONS 639,645 5/1964 Belgium ..71/98 PrimaryExaminer-Lewis Gotts Assistant ExaminerG. Hollrah Att0rneyFred L. Kelly[57] ABSTRACT AlkyI-N-aIkyI-chlorophenoxythioacetimidates are preparedby reacting N-alkyI-dior trichlorophenox- 3 Claims, No DrawingsALKYL-N-ALKYL- CHLOROPHENOXYTHIOACETIMIDATES BACKGROUND OF THE INVENTIONThis is a division of application Ser. No. 839,078, filed July 3, 1969,now US. Pat. No. 3,647,413.

This invention relates to novel chlorophenox ythioacetimidates; inparticular, it relates to alkyl-N- alkyl-chlorophenoxythioacetimidates,their preparation and use as herbicides.

The need to control undesirable plant growth for efficient cultivationof crops has given rise to the development of a great variety ofherbicidal agents. However, many of the chemical herbicides availableheretofore do not have adequate potency or selectivity to afford optimumresults. An effective herbicide must be highly effective againstundesirable plants while remaining harmless with respect to the plantbeing cultivated, such as corn and wheat.

SUMMARY OF THE INVENTION The novel compounds of the instant inventionare diand trichlorophenoxythioacetimidates of the formula:

wherein R is hydrogen or chlorine, and R and R" are lower alkyls having1-4 carbon atoms.

These compounds are prepared by reacting N-alkyldiortrichlorophenoxythioacetamide with alkyl iodide in the presence of asodium alcoholate to form the corresponding alkyl-N-alkyl-diortrichlorophenoxythioacetimidates. The novel compounds are useful asherbicides.

DETAILED DESCRIPTION OF THE INVENTION Preparation of the instantcompounds is accomplished by reacting a lower alkyl iodide with theappropriate N-alkylchlorophenoxythioacetamide in the presence of anequivalent amount of a sodium alcoho- R Approximately equimolar amountsof the two substrates may be used, although an excess of either might beused to achieve a higher yield with respect to the other.

The reaction may be conducted in an inert solvent; it is convenient touse an alcohol which is a by-product of the synthesis. Preferably, thereaction will be conducted at a temperature within the range of -70C.,and more preferably, -45C. Reaction times as short as about one-halfhour or less have been found to be adequate, although longer reactiontimes may be used if desired. Atmospheric pressure is normally used forthe reaction, although subatmospheric or superatmospheric conditionsmight be employed.

Substrate materials are readily available by procedures taught in theprior art. For example, the various chlorophenoxythioacetamides might beprepared by reacting the appropriate chlorophenoxyacetonitrile withalcoholic solution of ammonia and hydrogen sulfide (Fritzsche, Journalof Pracktische Chimie (2) 20, 279). The correspondingN-alkylchlorophenoxythioacetamides may be prepared by reacting thethioacetamides with an alkylamine. Alkyl iodide is availablecommercially.

The instant compounds have been found to be unexpectedly effectiveherbicides in that they are very harmful to plants normally consideredundesirable, such as rape and broadleafed weeds, while being relativelyharmless toward such plants as corn and wheat.Methyl-N-methyl-2,4-dichlorophenoxythioacetimidate is the preferredcompound for this purpose; it is especially useful as a preemergenceherbicide and is effective against crabgrass.

Normally, the instant compounds will be used as the active ingredient inan herbicidal composition, although they might also be used without acarrier. Various diluents and carriers may be employed and the percentof active ingredient may be varied. Although compositions with less thanabout 0.5 percent by weight of active ingredient may be used, it ispreferable to use compositions containing at least about 1.0 percent ofactive ingredient because otherwise the amount of carrier becomesexcessively large. Activity increases with the concentration of activeingredient, which may be 10, 50,95 percent or even higher.

The amount of composition which is applied for effective herbicidalaction is dependent upon considerations such as the type of undesirableplant to be killed, the density of undesirable plants, and soil andclimatic conditions. Usually, sufficient composition will be applied toprovide about 8 to 16 pounds of active ingredient per acre.

The instant herbicidal compositions may be in the form of a solution,with the solvent being selected from acetone, dichloromethane and thelike. These solutions can be applied to the plants in a direct mannersuch as by spraying, sprinkling, drenching, etc. Water suspensions canalso be applied in this manner, with dispersing and emulsifying agentssuch as sodium alkyl sulfates and sulfonates and the like.

Application can also be achieved by dusting a powder in which the activeingredient is dispersed. Suitable carriers include finely powderedmaterial such as clays, fullers earth, talc, etc.

The instant compounds may constitute the sole active ingredient in theherbicidal compositions, but they might be effectively used incombination with other active ingredients, such as other herbicides,insecticides and other plant treating agents.

The following examples are provided to more fully illustrate the instantinvention. They are provided for illustrative purposes only and are notto be construed as limiting the scope of the instant invention, which isdefinied by the appended claims.

EXAMPLEI Preparation of Methyl-N-Methyl-2,4-Dichlorophenoxythioacetimidate stirrer, and a thermometer. About 1.4grams of sodium methylate in 20 ml of absolute ethanol was then addedslowly with stirring to the mixture over a period of minutes whilemaintaining the temperature of the mixture between 40 to 45C. Themixture was heated at 40 to 45C. and stirred for another 15 minutes,until about neutral, as indicated by the disappearance of the redphenolphthalein color. Water was then added to the mixture and themixture was filtered. The separated solid material was mixed with 25 mlof methanol and the mixture was filtered. The separated solid was dried.

Yield was 3.5 grams, melting between 86 to 88C. A melting point of 88 to89C. was obtained by recrystallizing from methanol.

Analysis Calculated Found Carbon, 45.5 45.3 Hydrogen, 4.2 4.2

EXAMPLE ll EXAMPLE lll Herbicidal Activity The following crop speciesand weed species were planted in metal flats (12 by 8.5 by 4 inches) ingreenhouse potting soil containing one-third mixed clay and 55 thefollowing sand, one-third mushroom soil, and one-third peat moss. The pHof the soil was 6.8 to 7.2.

Crop Species Corn, Zea mays, Hybrid US. 13 Wheat, Triticum vulgare,variety Thorne Weed Species Rape Crabgrass Each flat received a volumeof spray equal to 80 gallons per acre of an aceton soluti on ofmethyl-N- methyl-2,4,-dichlorophenoxyt ioacetimidate. The concentrationof the solution was adjusted to provide application of l6 pounds ofactive ingredient per acre. immediately after spraying, the test flatswere placed in aluminum trays and were irrigated until the surface ofthe soil in the flat was uniformly moist (at field capacity). Additionalsubirrigation was provided as needed to maintain moisture. No surfaceirrigation was applied.

The flats were sprayed within 1 day after seeding in preemergence tests,and 8 to 10 days after seeding in the postemergence tests. Results wereobserved 14 days after spraying.

The effect of the herbicides was evaluated in terms of the injury ratingindex scale, ranging from 0 to 10 as follows:

0 No apparent injury 1,2,3 Slight injury 4,5,6 Moderate injury 7,8,9Severe injury (plants will die) 10 Plants were dead An injury rating of3 is the maximum tolerated for crops and a rating of 7 is the minimumacceptable on weed plants.

Injury Rating Plant Preemergence Postemergence Corn 2 4 Wheat 2 4 Rapel0 I0 Crabgrass 8 I claim: 1. Compounds of the formula:

wherein R is hydrogen or chlorine, R is a lower alkyl, and R" is a loweralkyl.

2. Compounds of claim 1 wherein R is hydrogen. 3. Compound of claim 1wherein said compound ismethyl-N-methyl-Z,4-dichlorophenoxythioacetimidate.

i i i

1. Compounds of the formula: wherein R is hydrogen or chlorine, R'' is alower alkyl, and R'''' is a lower alkyl.
 2. Compounds of claim 1 whereinR is hydrogen.